Wednesday, December 10, 2008

A bad case of the blues

After leaving my trusty Canon digital camera in the back of a cab while attending a tradeshow in Las Vegas, I was forced to purchase another. Upon visiting the local Best Buy with the name and model number of the camera that I had inadvertently mislaid, I was informed by the salesman that the camera I had previously purchased was no longer in production. My lost 6-Mpixel camera had been replaced by another, less expensive model, with a lot more features and an 8-Mpixel sensor.

Since I hoped my publishing company would pay for the camera, I decided to purchase said 8-Mpixel product and surprise them with the savings I had made. After using the camera to take numerous images of my son's recent graduation, however, I developed a bad case of the blues. Actually, it was a bad case of the lack of blues. Specifically, the blue response of the sensor was not comparable to that of the previous camera. Luckily for consumers like me, such effects can be compensated by some digital trickery embedded in Adobe Photoshop.

While some planned obsolescence by camera manufacturers may be good for the consumer, for system integrators, theseeffects on industrial cameras, frame grabbers, lighting, and other types of automation products can be much more serious. Imagine, for example, you have developed a machine-vision system designed to examine the color of potato chips and then automatically sort them as either good or bad. From the numerous types of camera vendors, you choose an RGB camera with a simple FireWire interface, interface it to a PC, and write some code to perform the color analysis. Based on this analysis, the PC then initiates a PLC and a remote actuator to sort the chips.

After a year of the machine working perfectly, vibration effects cause the camera to break, requiring a replacement. To yourhorror, you find that the upgraded, lower-cost replacement you install rejects every chip as bad. Needless to say, capturing each image and adjusting it manually in Adobe Photoshop is simply out of the question!

After hours of frustration and wasted production, it's time to call the camera company, where you are informed that it reallyisn't their fault at all. Rather, the blame lies with the CCD vendor that has upgraded its CCD line, making obsolete the original CCD and thus the camera vendor's original camera line.

To shift everyone's share of the blame, the camera vendor suggests that you remap your color space model to compensate for the new RGB spectral curves of the camera and everything should work as before. Not knowing anything about what software you originally used in the application, however, this is all the advice that you receive. What then follows can then only be mitigated by copious amounts of Vicodin and hair pulling.

Unfortunately, this sad state of affairs is not simply the problem of camera vendors. Similar problems can also occur when lenses, lighting, frame grabbers, CPUs, and software need to be replaced. Worse, when smaller manufacturers go out of business, their product lines are often no longer available, making any comparable replacement parts more difficult to find.

Often, I have heard stories from system integrators who have been tasked to replace complete machine-vision systems because many of the components and software of older installed systems can no longer be upgraded. In the mechanical automation industry, mechanical engineers can often replace parts such as CPUs, PLCs, and pneumatic actuators with a number of comparable parts from a host of well-known suppliers. Adding machine vision to such systems, however, is often fraught with danger since machine-vision standards and standard-compatible products still need to be developed.

Perhaps the only solution to this problem will lie in the development of a number of plug-compatible smart cameras from numerous vendors. With integrated optics, sensors, software, and I/O, products like these may become as commonplace as the PLC and just as easy to interface and replace.

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